JIAHON is not the authorized distributor of CAHO in Taiwan.
CAHO SR-R2540 solid state relay (SSR) | AC 40 A · VR phase control · heater temperature control
VR-AC phase control · input AC 90–250 V · output AC 24–250 V 40 A · stepless power adjustment · 2500 V isolation
In one line: the CAHO SR-R2540 is a VR phase-control solid state relay with AC 110–250 V control input and AC 24–250 V / 40 A output. A built-in B250 kΩ potentiometer gives stepless power adjustment, and with no mechanical contacts there is no arcing, making it suitable for continuous high-power temperature control on heaters, heating elements and ovens.
Specifications
| Item | SR-R2540 |
|---|---|
| Model / type | SR-R2540 / VR-AC phase-control SSR |
| Input voltage (I/P) | AC 110–250 V (operating range AC 90–250 V) |
| Output voltage (O/P) | AC 24–250 V |
| Output current | 40 A rated (≤35 A with heat sink recommended in practice) |
| Control | Stepless power adjustment by VR (B250 kΩ potentiometer) |
| Isolation voltage | 2500 V RMS (input / output / case) |
| Operating temperature | −20 to +80°C |
| Cooling | Built-in aluminum base; add a forced-air fan for high-current use |
| Weight | Approx. 70 g |
Phase-control SSR vs zero-cross SSR
| Item | SR-R2540 (phase control VR-AC) | Zero-cross SSR |
|---|---|---|
| Output power control | 0–100% stepless | Full on / full off only |
| Temperature control precision | High (fine control of heating power with a temperature controller) | Lower (relies on cycle ratio) |
| EMI | Harmonics during phase switching; watch power quality | Switches at zero crossing; lower EMI |
| Loads | Purely resistive loads such as heating elements and resistance heaters | General switching, lighting |
| Typical use | Temperature control of ovens, injection molding machines, heat presses | ON / OFF switching of general equipment |
Installation and use
- Heat sink required: at high current (>20 A) in continuous operation the SR-R2540 heats up noticeably; always fit a heat sink or forced-air cooling, or SSR life will be greatly shortened.
- Keep current ≤35 A in practice: leaves margin for inrush current and changes in ambient temperature.
- VR adjustment: the B250 kΩ potentiometer sets the output power ratio; turn clockwise to increase output, and set it to minimum before powering up to avoid a surge.
- Upstream protection: put a suitably rated circuit breaker (such as Siemens 3RV or Schneider iC65N) in series on the output side for short-circuit protection.
Related: Siemens circuit breakers (SIRIUS 3RV / SENTRON MCB) · Schneider circuit breakers (Acti9 iC65N / NS800H)
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